Aircraft are commonly equipped with Cabin Pressure Control Systems (CPCSs), which maintain cabin air pressure within a desired range to increase passenger comfort during flight. A typical CPCS may include a controller, an actuator, and an outflow valve. The outflow valve is typically mounted on either a bulkhead of the aircraft or on the outer skin surface of the aircraft, and selectively fluidly couples the aircraft cabin and the atmosphere outside of the aircraft. During operation, the controller commands the actuator to move the outflow valve to various positions to control the rate at which pressurized air is transferred between the aircraft cabin and the outside atmosphere, to thereby control the pressure and/or rate of change of pressure within the aircraft cabin. The controller may be configured to command the actuator to modulate the outflow valve in accordance with a predetermined schedule or as a function of one or more operational criteria. For example, the CPCS may additionally include one or more cabin pressure sensors to sense cabin pressure and supply pressure signals representative thereof to the controller. By actively modulating the outflow valve, the controller may maintain aircraft cabin pressure and/or aircraft cabin pressure rate of change within a desired range.
In some aircraft, the outflow valve may be positioned on the aircraft outer skin surface such that, when pressurized air is exhausted from the cabin, the exhausted air may provide additional forward thrust to the aircraft. Thus, outflow valves may sometimes be referred to as thrust recovery valves. Modern thrust recovery valves often include two valve door elements with multiple actuation linkages to enable proper sealing, reduce drag, and optimize valve door positioning for cruise thrust creation. Some earlier thrust recovery valves include a single, scoop-type valve door. These single valve doors are typically hinged on an end of the trailing edge. While this configuration makes the valve door aerodynamically acceptable, it can also make the actuation torque needed to drive the valve undesirably large. This, in turn, can result in relatively large and relatively expensive actuators and drive linkages being used.
Single valve door thrust recovery valves with the hinge point midway on the valve door, to thereby reduce the drive torque, have been envisioned. Unfortunately, these single valve door thrust recovery valves exhibit certain drawbacks. For example, in order to move the valve to the positions necessary to both seal and to not protrude during aircraft cruise operations, the valve door must be located inboard of the fuselage skin, which creates unwanted drag.
Hence, there is a need for a single valve door thrust recovery valve that does not rely on a relatively large and expensive actuator to move it, and/or does not create unwanted drag during aircraft cruise operations. The present invention addresses at least these needs.